class Integer
    def divide
        return 4.0 / (self * 2 - 1);
    end
end

answer = 4.0 / 1
c = 2

while c < 10000000 do
    if (c % 2 == 0) then
        puts (answer = answer - c.divide)
    else
        puts (answer = answer + c.divide)
    end
    c += 1
end